Polymeric materials exhibiting both thermoplastic as well as elastomeric characteristics have a variety of unique properties that make them valuable articles of commerce. Such thermoplastic elastomers include block copolymers having the general structure of ABA (linear triblock), A(BA)n (linear alternating block), or (AB)n-X (radial block) where A is a thermoplastic, glassy block with a high glass transition temperature, B is an elastomeric block, n is a positive whole number, and X is the initiator core or residue.
Thermoplastic elastomers can behave like vulcanized rubbers at room temperature and like thermoplastic polymers at higher temperatures. Thus, the materials can be melt extruded like plastics, while retaining their beneficial rubbery or elastic features upon cooling. This ability is not only advantageous during polymer processing, but actually allows for reprocessing as well. Furthermore, not only are such products fundamentally elastomeric but they exhibit physical behavior similar to elastomers that have been reinforced with reinforcing agents. In other words, the products behave substantially in the same manner as vulcanized rubbers, but without the need to subject them to vulcanization, which is often impractical because of the nature of the product being produced, for example, adhesives, coatings, elastic threads, biological implants, or medical device coatings.
Polymers having such dual nature have been known for some time but their application in biomedical and pharmaceutical fields may have been hindered due to the time, difficulty, and/or expense associated with purifying such polymers for biomedical and pharmaceutical applications. Accordingly, there is a need in the art for improved methods of polymer synthesis and/or purification as it relates to thermoplastic elastomers.